1. Field
The present specification generally relates to methods and apparatuses for fabricating continuous glass ribbons and, more particularly, to methods and apparatuses for mitigating distortion during fabrication of continuous glass ribbons.
2. Technical Background
Continuous glass ribbons may be formed by processes such as the fusion draw process, the slot draw process, or other similar downdraw processes. The fusion draw process yields continuous glass ribbons which have surfaces with superior flatness and smoothness when compared to glass ribbons produced by other methods. Individual glass sheets sectioned from continuous glass ribbons formed by the fusion draw process can be used in a variety of devices including flat panel displays, touch sensors, photovoltaic devices, and other electronic applications.
Continuous glass ribbons formed by the fusion draw process may bow or curve in a lateral direction due to temperature gradients in the glass as it cools. In particular, when a continuous glass ribbon emerges from a fusion drawing machine, the glass ribbon may bow or curve due to the difference in temperature between the edges of the glass ribbon (which tend to be thicker and cool slower) and the central portion of the glass ribbon (which tends to be thinner and cool faster). Distortions in the glass ribbon below the fusion drawing machine tend to propagate to the bottom of the draw where individual sheets of glass are sectioned from the ribbon by supporting the glass ribbon with a nosing device as the glass ribbon is scored and separated. Specifically, when a glass sheet is scored and separated from the continuous glass ribbon using a traveling anvil machine, a nosing device may be used to support the continuous ribbon during scoring. Engaging the scoring device with a curved glass ribbon tends to introduce stress into the glass ribbon which may distort or break the glass ribbon during scoring. Furthermore, the contact between the scoring device and the curved glass ribbon may also introduce motion in the ribbon which is propagated upstream of the scoring device and causes undesirable stress and warp in the ribbon.
Accordingly, alternative methods and apparatuses for fabricating continuous glass ribbons that mitigate distortion of the continuous glass ribbon are disclosed.